Mimas [MY-mass] is one of the innermost moons of Saturn.
Mimas was a Titan who was slain by Hercules.
William Herschel discovered
the moon in 1789. The surface is icy and heavily cratered.
Mimas has a low density, meaning it probably consists mostly of ice.
Because Mimas has such a low temperature of about -200° C
(-328°F), the impact
features may date back to the time of the moon's creation.

One of the craters, named Herschel, is surprisingly large
in comparison to the size of the moon. The crater
is 130 kilometers (80 miles) wide, one-third the
diameter of Mimas. Herschel is 10 kilometers (6 miles) deep,
with a central mountain almost as high as Mount Everest on Earth.
This central peak
rises 6 kilometers (4 miles) above the crater floor.
This impact probably came close to disintegrating the moon.
Traces of fracture marks can be seen on the opposite side of Mimas.

Although Mimas is heavily cratered, the cratering is not uniform.
Most of the surface is covered with craters greater than 40 kilometers
(25 miles) in diameter but in the south polar region, craters greater than
20 kilometers (12 miles) are generally lacking. This suggests that some
process removed the larger craters from these areas.

Mimas & Herschel Crater
This image of Mimas was acquired by the Voyager 1 spacecraft on
November 11, 1980 from a range of 425,000 kilometers (264,000 miles).
The large crater on the right limb is named Herschel. It
is 130 kilometers (80 miles) wide and one-third the
diameter of Mimas. Herschel is 10 kilometers (6 miles) deep,
with a central mountain almost as high as Mount Everest on Earth.
This impact probably came close to disintegrating the moon.
(Copyright Calvin J. Hamilton)

Mimas & Herschel Crater
This is another image of Mimas and the Herschel Crater impact. It
was acquired by the Voyager 1 spacecraft on
November 11, 1980.
(Copyright Calvin J. Hamilton)

Mimas
This image of Mimas was acquired by the Voyager 1 spacecraft on
November 13, 1980. Traces of fracture marks, probably due to the
Herschel Impact, can be seen on this side of Mimas.
(Copyright Calvin J. Hamilton)

Mimas
This is another image of Mimas acquired by the Voyager 1 spacecraft on
November 13, 1980. The surface is heavily cratered indicating an
ancient surface age.
(Copyright Calvin J. Hamilton)